avcodec/libdav1d: use the library default for the filmgrain option

Signed-off-by: James Almer <jamrial@gmail.com>

doc/decoders.texi

@@ -57,7 +57,7 @@ You need to explicitly configure the build with @code{--enable-libdav1d}.
 
 @subsection Options
 
-The following option is supported by the libdav1d wrapper.
+The following options are supported by the libdav1d wrapper.
 
 @table @option
 
@@ -68,8 +68,8 @@ Set amount of frame threads to use during decoding. The default value is 0 (auto
 Set amount of tile threads to use during decoding. The default value is 0 (autodetect).
 
 @item filmgrain
-Apply film grain to the decoded video if present in the bitstream. The default value
-is true.
+Apply film grain to the decoded video if present in the bitstream. Defaults to the
+internal default of the library.
 
 @end table
 

libavcodec/libdav1d.c

@@ -131,7 +131,8 @@ static av_cold int libdav1d_init(AVCodecContext *c)
     s.allocator.alloc_picture_callback = libdav1d_picture_allocator;
     s.allocator.release_picture_callback = libdav1d_picture_release;
     s.frame_size_limit = c->max_pixels;
-    s.apply_grain = dav1d->apply_grain;
+    if (dav1d->apply_grain >= 0)
+        s.apply_grain = dav1d->apply_grain;
 
     s.n_tile_threads = dav1d->tile_threads
                      ? dav1d->tile_threads
@@ -342,7 +343,7 @@ static av_cold int libdav1d_close(AVCodecContext *c)
 static const AVOption libdav1d_options[] = {
     { "tilethreads", "Tile threads", OFFSET(tile_threads), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, DAV1D_MAX_TILE_THREADS, VD },
     { "framethreads", "Frame threads", OFFSET(frame_threads), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, DAV1D_MAX_FRAME_THREADS, VD },
-    { "filmgrain", "Apply Film Grain", OFFSET(apply_grain), AV_OPT_TYPE_BOOL, { .i64 = 1 }, 0, 1, VD },
+    { "filmgrain", "Apply Film Grain", OFFSET(apply_grain), AV_OPT_TYPE_BOOL, { .i64 = -1 }, -1, 1, VD },
     { NULL }
 };
 

libavcodec/version.h

@@ -29,7 +29,7 @@
 
 #define LIBAVCODEC_VERSION_MAJOR  58
 #define LIBAVCODEC_VERSION_MINOR  56
-#define LIBAVCODEC_VERSION_MICRO 101
+#define LIBAVCODEC_VERSION_MICRO 102
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \